The phrase a child calls a person that's much better off without him/her, in hopes that it will somehow lower that person's self esteem. It can also be used when an ex is in a full on rage, and doesn't know how to execute a proper insult, so they end up just calling you a snotty trick and thinking they're the shit.

My EX is a snotty trick because im jealous of how much better off she is without me.